The present invention relates to wound dressings and, more particularly, to a transparent, flexible wound dressing product containing a hydrogel substance.
Secreting skin wounds, such as decubitus ulcers and open surgical wounds, have long presented a medical challenge in keeping such wounds sterile and relatively dry. The accumulation of wound exudate, such as blood, pustulation and other wound fluids, in wound crevices promotes growth of bacteria and crusted organisms which cause infection and delay the healing process. However, since it is often desirable to allow a wound to heal in a slightly moist or occlusive state, as it is believed that this may accelerate healing, excess wound exudate must be removed. If excess wound exudate remains on a wound, a "blister" of exudate can form under the wound dressing which is not only unsightly, but also may cause the dressing to leak, thereby defeating the aim of sterility. Existing methods of aspiration, however, can lead to wound infection or can destroy sterility. Additionally, it is not desirable to remove all exudate, as that would result in a dry wound and, hence, a slower healing process.
Known aqueous moisture-absorbing wound dressing systems have additional problems in that the aqueous material is generally contained in the center portion of a wound dressing, with a bulky adhesive border, such as a foam border. Problems with such borders include decreased comfort, conformity and adhesion, as well as the existence of a "lifting edge" that can catch on clothes or bed sheets, thereby exposing the wound to bacteria and infection. In addition, observation of the wound by medical personnel may require lifting the wound dressing, thereby exposing the wound, again creating a situation where bacteria and infection can be introduced to the wound site.
Adhesive wound dressings, similar to that disclosed by Ward, U.S. Pat. No. 4,753,232, issued Jun. 28, 1988, are frequently constructed of a polymer film having one adhesive surface. The polymer film is extremely thin and, therefore difficult to handle during application to the wound. Further, it is desirable to apply the wound dressing to the patient's skin without touching the surface of the dressing that is to come into contact with the skin. The prior art discloses several methods for facilitating handling of the wound dressing. Ward, for instance, discloses a "handle" portion along one edge of the dressing. After the dressing is applied, the handle may be removed by tearing, or it may carry an adhesive coating so that it may be adhered to the skin of the patient.
An existing method of avoiding contact with the edges of a bandage by fingers or forceps is disclosed in Brower, U.S. Pat. No. 4,646,731, issued Mar. 3, 1987. Brower discloses an adhesive-coated bandage whose edges are protected by a pair of folded V-shaped tabs. After the backing sheet is removed from the bandage, one tab is removed and the corresponding end of the bandage is applied to the skin. The second tab is grasped and removed as the entire length of the bandage is then applied.
Faasse, Jr., U.S. Pat. No. 4,744,355, issued May 17, 1988, solves a problem associated with excessive peeling force during removal of backings from wound dressings. The Faasse patent teaches a release liner adhesively attached to each end of a wound dressing strip (covering layer). A hinge arrangement is provided between each release liner and the dressing. As the release liners are pulled away from the wound dressing strip, the hinge means are employed, thus reducing the peeling force on the covering layer and preventing the liners from pulling away from the covering layer prematurely.
United Kingdom Patent Application No. 2,128,479 describes a surgical dressing with two release sheets, each covering half of the dressing and having a free edge curved at the center of the dressing. As the curved edges of the release sheets are peeled back, the center of the dressing is applied to the wound, followed by the ends, thereby preserving sterility by eliminating the need to touch the adhesive surface of the dressing.
European Patent Application Pub. No. 0 168 174 discloses a relatively rigid carrier section with bent handles over the outer surface of a thin-film dressing. The carrier section aids in keeping the dressing extended during application and prevents the ends from curling. The reference further discloses a tab portion along one edge of the dressing. This tab portion is not coated with adhesive. It may be grasped during application of the dressing to the patient's skin and is removable afterward by tearing.
Our own commonly-assigned U.S. Pat. No. 5,106,629, issued to Cartmell et al. on Apr. 21, 1992, discloses a hydrogel wound dressing with a thin-film transparent layer, a dimensionally stable backing layer over the outer surface of the transparent layer, and a release liner. The backing layer and the release liner each have a corner tab to facilitate the peeling of each from the transparent layer. The hydrogel material is positioned in a center portion of the transparent layer, and the adhesive perimeter portion of the transparent layer adheres to the skin of the patient. The dimensionally stable backing member prevents the transparent layer from curling and facilitates handling of the dressing during its application.
Only the Cartmell et al. reference discloses a wound dressing containing a hydrogel material for the absorption of wound exudate. Further, the means taught by the aforementioned references for facilitating the handling of a thin-film wound dressing layer are fairly complicated and may involve substantial expense in manufacture and materials, particularly when viewed in relation to the overall cost of the wound dressing.
It is seen, therefore, that there is a need for a hydrogel wound dressing product that may be easily handled during application to the wound without touching the adhesive side of the dressing. Further, there is a need for a hydrogel wound dressing product that is inexpensive and simple to manufacture, and easily removed from a release liner and applied to a wound.